Intercommunication system



Filed Jan. 12, 1939 Fig. 3

#9960 Mksszzer Patented Aug. 20, 1940 UNITED STATES INTERCOMMUNIOATION SYSTEM Alfred Wiessner, Berlin, Germany, assignor to C. Lorenz Aktiengesellschaft, Berlin-Tempelhof,

Germany, a company Application January 12, 1939, Serial No. 250,460 In Germany January 4, 1938 6 Claims.

The invention is a continuation in part of the copending patent application Serial No. 223,019,

filed August 4, 1938, for Carrier frequency communication systems.

This prior application is concerned with an arrangement for use in connection with telephone network, namely, the network of telephone systems which also serves for transmitting come munications by means of carrier frequencies and especially for broadcast purposes. The arrangement there disclosed aims to provide for interrupting in a simple manner the low'frequency line without thereby interrupting the high frequency line, or vice versa. Preferably, the high frequency energy is to be supplied through the connection strips, also termed as terminal strips and arranged in the well known main distributors. The low-pass and high-pass filters of this arrangement are formed as plug devices adapted to be separately inserted in place.

The invention described hereafter has for its object to improve arrangements of this type by comprising the lowpass filters in groups which by preference are to be invariably attached to all the outgoing lines, whereas the high-pass filters are formed as plug devices.

In the accompanying drawing one embodiment of the invention is illustrated by way of example.

Fig. 1 is a diagrammatic perspective view of a main distributor. Fig. 2 is a plan representing one of the connecting strips ofv this distributor, Fig. 3 a fragmentary elevation of this connecting strip.

Fig. 1 shows connecting strips L mounted in a frame V and intended for the connection of the incoming and outgoing line wires of the telephone exchange.

As represented in Figs. 2 and 3, such a connecting strip comprises a plurality of soldering tabs I, located above one another. These soldering tabs are comprised in a strip-shaped assembly and are fixed to carriers 2, forming part of frame V. The high-pass filters 3, belonging to the individual lines, are likewise arranged above each other. These filters are formed as plug devices provided with a handle 4 for withdrawing them from their casing 5 and thereby interrupting the high frequency supply line. Casing 5, which thus serves to carry the high-pass filters, is fitted with soldering tabs 6, to which the lines for the incoming and outgoing high frequency currents are connected.

In order to reduce to a minimum the space required for the low-pass filters, these are comprised in groups of five each, located in a box I and provided with suitable soldering tabs. In

this way the low-pass filters may be mounted in the main distributor without the place requirements being much greater than in the case of arrangements not adapted to receive high frequency energy.

The construction here shown by way of example is designed for twenty line wires to each 10 connecting strip, so that there are four boxes I if as stated five low-pass filters are contained in each such box.

What is claimed is:

1. System for combined telephone and carrier frequency transmission, comprising a distributing frame carrying a number of pairsof line terminals, a number of subscribers lines connected to said line terminals, a number of low frequency lines extending to said frame for low frequency connection to said line terminals, a number of high frequency lines extending to said frame for high frequency connection to said terminals, a plurality of groups of low-pass filters, a plurality of housings mounted on said frame each encasing one of said groups of filters and. each carrying a plurality of terminals for connecting the several filters of said group between several of said low frequency and several of said line terminals, a number of plug-in receptacles mounted on said frame and each carrying terminals for connection between one of said high frequency lines and one pair of line terminals, and a number of high-pass filter units each adapted to plug into one of said receptacles and simultaneously make connection with said terminals carried by such receptacle, whereby the connection between any subscribers line and its associated high frequency line may be readily interrupted merely by removing the corresponding high-pass filter unit while maintaining unbroken the connection between such telephone line and the corresponding low frequency line.

2. System according to claim 1, wherein each of said groups of low-pass filters comprises approximately five filters.

3. System according to claim 1, wherein said plurality of groups of low-pass filters comprise one such low-pass filter per subscribers line,

, whereby each subscribers line extending to said distributing frame is connected to a low-pass filter.

4. System according to claim 1, wherein a plurality of said number of plug-in receptacles are formed in a single casing common to a plurality of said high-pass filter units.

5. System according to claim 1, wherein a plurality of said pairs of line terminals carried by said distributing frame are comprised in a strip shaped assembly and wherein a plurality of said housings and a plurality of said receptacles are each united into the strip shaped assembly sep- 

